Especially when said Armor is made out of (hard) plastic, steel or something similar strong metal. You’d just get hurt yourself, and might not be able to take the armor off if the beak is fully developed, which could prove to be quite hazardous.
Would it be able to make several groups of ‘armors’ which react differently to mutations?
simple Cloth and thin plastic might just rip after a while, giving you at least some scraps.
Soft plastic and Leather might get damaged, but wouldn’t necessarily be unusable. It would definitely be deformed though, means, you would get a badly damaged piece of equipment which would require repairs - you could also use it to craft something that actually fits your new mutation.
Hard plastic, steel, ceramic wouldn’t get damaged, unless the mutation would be extremely sharp and/or sturdy. Chances are, the player would get hurt by keeping that equipment on, because it wouldn’t give the mutation space to grow. Worst case scenario would be that you couldn’t even remove said equipment anymore, because the new mutation locks it all in place. You would require tools of some kind in order to get rid of the equipment. This is especially bad if it’s a helmet or something similar, which could stop you from eating, drinking or in some cases might even restrict breathing. It would probably also add a lot of encumberment to the body part until it is removed.